1. Field of the Invention
The present invention relates to an organic EL device and a method for manufacturing the same.
2. Description of Related Art
An organic EL device includes an anode receiving positive voltages and a cathode receiving negative voltages. The organic EL device also has an EL light-emitting layer that emits light by itself. The EL light-emitting layer emits light by recombining holes transferred from the anode electrode and electrons transferred from the cathode electrode.
Such organic EL devices are recently used in various industrial fields, for example, a back light device for a liquid crystal display (LCD) device, a portable terminal apparatus, an automobile navigator, a computer, a television, and so on because of its rapid response speed, excellent brightness, simple structure, low production costs and light weight.
The organic EL device is manufactured in the following manner. First, indium tin oxide (Transparent Conductive Materials) layer is deposited on a transparent substrate and is patterned into an anode receiving positive voltages. The anode is formed on a display region, but the anode lead and the cathode lead are formed on a non-display region.
A first photoresist layer is deposited over the display region covering the anode electrode. The first photoresist layer goes through a photolithography using a first mask having an opening portion on a location corresponding to pixel regions, to form an insulating layer on a portion of the anode electrode other than portions corresponding to the pixel regions.
Subsequently, a second photoresist is coated to a predetermined thickness on the insulating layer. At this time, an opening portion of a stripe-like shape crossing over the display region is formed on a location corresponding to a space between the cathode leads. On the other location, after aligning a second mask with the second photoresist, the second photoresist is exposed to light and is later developed to form partition walls having an inverted trapezoid shape. At this point, the second photoresist is made of a different material from the first photoresist.
Thereafter, an organic material is deposited on the display region to form the EL light-emitting layer on an exposed surface of the anode electrode. A metal layer is deposited on the display region to form the cathode electrode between the partition walls. At this point, the pixel regions are where the EL light-emitting layer and the cathode layer are sequentially stacked on the anode electrode. As a result, most components of the organic EL device are completed.
Manufacturing the organic EL device using the above-described method, requires lengthy processing time, resulting in a low productivity, because a photolithography process such as the photoresist coating process, a light exposure process, a development process is performed both in forming the insulating layer and in forming the partition walls
To overcome the above-describe problems, preferred embodiments of the present invention provide a method for manufacturing on organic EL device in a short processing time.
It is another object of the present invention to provide an organic EL device having a low production cost.
It is also another object of the present invention to provide an organic EL device with high productivity.
In order to achieve the above object, the preferred embodiments of the present invention provide a method for manufacturing an organic EL device on a transparent substrate including a display region and a non-display region, the display region having pixel regions, including: forming first electrodes, and first and second leads on the transparent substrate, the first electrode spaced apart from each other, connected with the first leads, and formed on the display region, the first and second leads formed on the non-display region; depositing a photoresist over the whole surface of the transparent substrate while covering the first electrode; aligning first and second mask while interposing the transparent substrate therebetween; forming an insulating layer and partition walls on a region of the display region other than the pixel regions; forming an EL light-emitting layer on the pixel regions; and forming second electrodes on the EL light-emitting layer, the second electrode spaced apart from each other and perpendicular to the first electrode and connected with the second leads.
The photoresist is a chemically amplified resist. Forming an insulating layer and partition walls includes exposing the photoresist to an UV light through the first and second masks; and immersing the photoresist into a developer. The EL light-emitting layer includes the hole transport layer, the luminescent layer, and the electron transport layer. The first electrode is made of indium tin oxide. The photoresist further includes an ultraviolet absorbing agent.
The method for manufacturing the organic EL device according to the preferred embodiment of the present invention has the following advantages. Since the insulating layer and the partition wall are formed through one photolithography process, the manufacturing process is simplified, and the processing time becomes short, leading to a high productivity. Also, the insulating layer and the partition wall are formed using the same photoresist, the production cost becomes lowered.